Blaser Lab Group

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Members of Blaser Lab Group

Martin J. Blaser, MD

Martin J. Blaser, MD , Prinicpal Investigator

Frederick H. King Professor of Internal Medicine and Chairman of the Department of Medicine; Professor of Microbiology

Departments of Medicine (ADMINISTRATION) and Microbiology


Biology of Bacterial Persistence in Mammalian Hosts

Microbes that are able to persist in their hosts are subject to different selective pressures than are those that transiently infect, and either kill their host or are themselves eliminated. In mammals, the gastrointestinal and genital tracts represent biological niches that usually are populated by colonizing bacteria. We have been interested in bacteria of the Campylobacter and Helicobacter species, highly diverse organisms that live in the mucus layer overlying the mucosal epithelium of mammals, including humans. H. pylori colonization increases risk for development of peptic ulcer disease and gastric adenocarcinoma. Conversely, its presence appears to protect against certain diseases of the esophagus. The focus in my laboratory is to explore the biology of H. pylori colonization and the nature of the interactions that lead to (or protect from) disease. Several avenues are being approached. We are examining the variation in particular oligosaccharide (Lewis) antigens on the H. pylori cell surface and the nature of the host forces that select for cells of particular phenotypes. Disciplines involved include molecular biology, genetics, and mathematics. We are using transgenic and knockout mice to test hypotheses related to both host factors and bacterial evolution. Other projects relate to restriction-modification systems that act as barriers to horizontal gene transfer, and to a metastable "pathogenicity island" in the H. pylori genome (cag island). A third area of work relates to recombination, endogenous mutation, and DNA repair to understand their roles and regulation in the generation of diversity.

Another important focus of our work is Campylobacter fetus, a pathogen of animals and humans. C. fetus cells are covered with S-layer proteins that allow the organisms to escape complement-mediated lysis, and that undergo antigenic variation. Exploring the molecular basis of variation, we have found that the S-layer proteins are encoded by a family of sapA homologs tightly clustered on the chromosome, and that a high frequency DNA inversion plays a critical role in variation. The inversion shows elements of both site-specific and homologous recombination. This is a highly tractable system to examine DNA recombination mechanisms, as well as for structure-function analysis of protein-carbohydrate (LPS) interactions, and the structural basis of antigenicity.
Finally, we are using PCR with conserved 165 ribosomal RNA specificities to define at a molecular level, the bacteria (and fungi) that are normally present in human host mileaus.


Medical Education
NYU 1973
Department of Medicine, University of Colorado Medical Center 1973-1974
Clinical Fellowships
Fellow in Infectious Diseases, Department of Medicine, University of Colorado Medical Center 1980
Board Certifications
Diplomate, American Board of Internal Medicine, subspecialty of Infectious Diseases; Internal Medicine 1977; Infectious Diseases 1980
Medical Interests
Infectious Disease
Other Responsibilities

Dr. Blaser is Past President of the Infectious Diseases Society of America and Founder of the Foundation for Bacteriology and the Virtual Museum of Bacteria. He served as Chair of the Board of Scientific Counselor of the National Cancer Institute, and of the Advisory Board for Clinical Research at the NIH. He was elected to the Institute of Medicine of the National Academy of Sciences in 2011. He is a member of the editorial boards of Cell Host and Microbe, mBio, Helicobacter, Emerging Infectious Diseases, Gut, and Microbiome.
[List of the most recent publications of Dr. Blaser and of the Blaser Lab Group Principal Investigators]


Martin J. Blaser, MD



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